 /*******************************************************************************
  * Copyright (c) 2004, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.runtime.preferences;

 import java.net.URL ;
 import org.eclipse.core.internal.preferences.AbstractScope;
 import org.eclipse.core.internal.preferences.PreferencesOSGiUtils;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.osgi.service.datalocation.Location;

 /**
  * Object representing the configuration scope in the Eclipse preferences
  * hierarchy. Can be used as a context for searching for preference
  * values (in the IPreferencesService APIs) or for determining the
  * correct preference node to set values in the store.
  * <p>
  * Configuration preferences are stored on a per configuration basis in the
  * platform's configuration area. (The configuration area typically
  * contains the list of plug-ins available for use, various settings
  * (those shared across different instances of the same configuration)
  * and any other such data needed by plug-ins.)
  * </p>
  * <p>
  * The path for preferences defined in the configuration scope hierarchy
  * is as follows: <code>/configuration/&lt;qualifier&gt;</code>
  * </p>
  * <p>
  * This class is not intended to be subclassed. This class may be instantiated.
  * </p>
  * @see Location#CONFIGURATION_FILTER
  * @since 3.0
  */
 public final class ConfigurationScope extends AbstractScope implements IScopeContext {

     /**
      * String constant (value of <code>"configuration"</code>) used for the
      * scope name for the configuration preference scope.
      */
     public static final String SCOPE = "configuration"; //$NON-NLS-1$

     /**
      * Create and return a new configuration scope instance.
      */
     public ConfigurationScope() {
         super();
     }

     /*
      * @see org.eclipse.core.runtime.preferences.IScopeContext#getName()
      */
     public String getName() {
         return SCOPE;
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.runtime.preferences.IScopeContext#getNode(java.lang.String)
      */
     public IEclipsePreferences getNode(String qualifier) {
         return super.getNode(qualifier);
     }

     /*
      * @see org.eclipse.core.runtime.preferences.IScopeContext#getLocation()
      */
     public IPath getLocation() {
         IPath result = null;
         Location location = PreferencesOSGiUtils.getDefault().getConfigurationLocation();
         if (!location.isReadOnly()) {
             URL url = location.getURL();
             if (url != null) {
                 result = new Path(url.getFile());
                 if (result.isEmpty())
                     result = null;
             }
         }
         return result;
     }
 }

